The experiments employ a picosecond laser and time-resolved single photon counting detection. To study the photon paths, a screen with a small pinhole was inserted in the container filled with water solution of polystyrene microspheres (20-200 mean free paths across a container). The screen with pinhole was used to probe the photon paths within the scattering medium. By varying the position of the pinhole in the medium, the time-resolved photon path distribution can be mapped out. The existence of well-defined time-resolved photon paths demonstrated by these experiments provides the basis for a three-dimensional optical tomographic scheme. The results were in excellent agreement with path integral solution of transport equation and deviated from paths calculated using diffusion approximation.